‘replSetReconfig’ will internally rewrite the requested config to give the new node’s MemberConfig (an entry in the ‘members’ section of the ReplicaSetConfig) a ‘newlyAdded’ field indicating that the set should not count it towards the current number of voters and that the primary of the set should automatically initiate a ‘replSetReconfig’ to remove the field once initial sync completes.

Define a ‘new node’ as any node with an ‘_id’ field that is not present in the current config.
This matches the definition used in Safe Reconfig.

Log any rewritten configs.